A photopolymerizable negative type of photosensitive resin composition has been used for various types of purposes such as a photoresist for manufacturing a color filter, an overcoat photoresist, a column spacer, and an insulating material having a light blocking property. In general, the photosensitive resin composition includes an alkali-soluble resin, a polymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiator, a solvent and the like. The photosensitive resin composition may be prepared by the following method comprising: applying the photosensitive resin composition on a substrate to form a film, exposing a predetermined portion of the film with radiation of radioactive rays using a photomask and the like, and forming a pattern by removing non-exposed portions by development treatment.
In recent years, the application of LCDs (liquid crystal display) is expanded toward monitors for desktop computers, LCT TVs and the like as well as monitors for notebook computers, thus, a concentration of pigment is increased in a color filter photoresist and the pigment is finely dispersed in order to obtain a high quality color. Hence, the residues of the color filter photoresist are formed in a great amount. The most representative method of reducing the residue of the photoresist is to increase an acid value (AV) of a binder polymer that is included in an alkali soluble resin for manufacturing a photoresist or to reduce a molecular weight (MW) thereof. However, there is a limit to increase the acid value of the binder polymer due to the compatibility with other constitution components and the removal of the pattern during the development, and the reducing a molecular weight may reduce the chemical resistance, thus, this is undesirable.
Therefore, in the art, in order to produce a photoresist that has excellent physical properties, there was a need to obtain a novel material capable of being used as an alkali soluble resin and various studies have been made to develop the novel material.